Slender Man Verdict: Teen Girl Avoids Prison Time for Stabbing

Two girls accused of stabbing a classmate 19 times believed they had to or a fantasy horror character called Slender Man could kill their families, a U.S. court has heard.

Anissa Weier egged on friend Morgan Geyser as she attacked Payton Leutner so the pair could avoid the wrath of supernatural character Slenderman. They're not taking issue with Weier having some mental illness, but say she was much more motivated by her fear of losing Geyser as a friend if she didn't go along with the plot. A jury trial on her case, which began Monday, was set to determine whether Weier was mentally ill when she committed the crime. All three girls were 12 years old at the time of the stabbing, three years ago.

During the trial, a psychologist testified that Weier developed a condition called shared delusional disorder, in which she came to share Geyser's delusion that Slenderman was real, CNN affiliate WISN reported.

Weier and co-defendant Morgan Geyser (GY'-zur) were accused of luring classmate Payton Leutner (LYT'-nur) to a wooded area in a suburban Milwaukee park and then attacking her.

One of the girl's former classmates, who was also interested in Slender Man, told the court she had discovered how to become the character's servant - by killing a friend.

'I'm very thankful to the jurors for taking the time to look at what was really going on with her, ' Weier's attorney Maura McMahon said.

The pair bonded over their obsession with Slender Man with Weier believing the mythical character could read her mind and would kill her or her family if she talked about him.

According to investigators, Anissa Weier and Morgan Geyser stabbed Payton Leutner in a suburban Milwaukee park in 2014, almost killing her. Westendorf was appointed by a judge to evaluate Weier, now 15, after her plea.

Slender Man first appeared on the internet in 2009. She added that Geyser is schizophrenic and Weier clung to her because she was lonely and depressed. She believed he would hurt her and her family if she didn't help commit murder.

One of the teens criminally charged with stabbing a classmate in 2014 to please the fictional character Slender Man will be sent to a mental institution instead of prison. Geyser, who did the actual stabbing, is scheduled to go on trial next month. That caused her to share in Geyser's belief that Slender Man was real. Weier pleaded guilty to attempted second-degree homicide due to mental illness as part of a plea agreement in August.